Loading...
Note: File does not exist in v6.13.7.
1/**
2 * aops.c - NTFS kernel address space operations and page cache handling.
3 *
4 * Copyright (c) 2001-2014 Anton Altaparmakov and Tuxera Inc.
5 * Copyright (c) 2002 Richard Russon
6 *
7 * This program/include file is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as published
9 * by the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program/include file is distributed in the hope that it will be
13 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program (in the main directory of the Linux-NTFS
19 * distribution in the file COPYING); if not, write to the Free Software
20 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23#include <linux/errno.h>
24#include <linux/fs.h>
25#include <linux/gfp.h>
26#include <linux/mm.h>
27#include <linux/pagemap.h>
28#include <linux/swap.h>
29#include <linux/buffer_head.h>
30#include <linux/writeback.h>
31#include <linux/bit_spinlock.h>
32
33#include "aops.h"
34#include "attrib.h"
35#include "debug.h"
36#include "inode.h"
37#include "mft.h"
38#include "runlist.h"
39#include "types.h"
40#include "ntfs.h"
41
42/**
43 * ntfs_end_buffer_async_read - async io completion for reading attributes
44 * @bh: buffer head on which io is completed
45 * @uptodate: whether @bh is now uptodate or not
46 *
47 * Asynchronous I/O completion handler for reading pages belonging to the
48 * attribute address space of an inode. The inodes can either be files or
49 * directories or they can be fake inodes describing some attribute.
50 *
51 * If NInoMstProtected(), perform the post read mst fixups when all IO on the
52 * page has been completed and mark the page uptodate or set the error bit on
53 * the page. To determine the size of the records that need fixing up, we
54 * cheat a little bit by setting the index_block_size in ntfs_inode to the ntfs
55 * record size, and index_block_size_bits, to the log(base 2) of the ntfs
56 * record size.
57 */
58static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
59{
60 unsigned long flags;
61 struct buffer_head *first, *tmp;
62 struct page *page;
63 struct inode *vi;
64 ntfs_inode *ni;
65 int page_uptodate = 1;
66
67 page = bh->b_page;
68 vi = page->mapping->host;
69 ni = NTFS_I(vi);
70
71 if (likely(uptodate)) {
72 loff_t i_size;
73 s64 file_ofs, init_size;
74
75 set_buffer_uptodate(bh);
76
77 file_ofs = ((s64)page->index << PAGE_SHIFT) +
78 bh_offset(bh);
79 read_lock_irqsave(&ni->size_lock, flags);
80 init_size = ni->initialized_size;
81 i_size = i_size_read(vi);
82 read_unlock_irqrestore(&ni->size_lock, flags);
83 if (unlikely(init_size > i_size)) {
84 /* Race with shrinking truncate. */
85 init_size = i_size;
86 }
87 /* Check for the current buffer head overflowing. */
88 if (unlikely(file_ofs + bh->b_size > init_size)) {
89 int ofs;
90 void *kaddr;
91
92 ofs = 0;
93 if (file_ofs < init_size)
94 ofs = init_size - file_ofs;
95 local_irq_save(flags);
96 kaddr = kmap_atomic(page);
97 memset(kaddr + bh_offset(bh) + ofs, 0,
98 bh->b_size - ofs);
99 flush_dcache_page(page);
100 kunmap_atomic(kaddr);
101 local_irq_restore(flags);
102 }
103 } else {
104 clear_buffer_uptodate(bh);
105 SetPageError(page);
106 ntfs_error(ni->vol->sb, "Buffer I/O error, logical block "
107 "0x%llx.", (unsigned long long)bh->b_blocknr);
108 }
109 first = page_buffers(page);
110 local_irq_save(flags);
111 bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
112 clear_buffer_async_read(bh);
113 unlock_buffer(bh);
114 tmp = bh;
115 do {
116 if (!buffer_uptodate(tmp))
117 page_uptodate = 0;
118 if (buffer_async_read(tmp)) {
119 if (likely(buffer_locked(tmp)))
120 goto still_busy;
121 /* Async buffers must be locked. */
122 BUG();
123 }
124 tmp = tmp->b_this_page;
125 } while (tmp != bh);
126 bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
127 local_irq_restore(flags);
128 /*
129 * If none of the buffers had errors then we can set the page uptodate,
130 * but we first have to perform the post read mst fixups, if the
131 * attribute is mst protected, i.e. if NInoMstProteced(ni) is true.
132 * Note we ignore fixup errors as those are detected when
133 * map_mft_record() is called which gives us per record granularity
134 * rather than per page granularity.
135 */
136 if (!NInoMstProtected(ni)) {
137 if (likely(page_uptodate && !PageError(page)))
138 SetPageUptodate(page);
139 } else {
140 u8 *kaddr;
141 unsigned int i, recs;
142 u32 rec_size;
143
144 rec_size = ni->itype.index.block_size;
145 recs = PAGE_SIZE / rec_size;
146 /* Should have been verified before we got here... */
147 BUG_ON(!recs);
148 local_irq_save(flags);
149 kaddr = kmap_atomic(page);
150 for (i = 0; i < recs; i++)
151 post_read_mst_fixup((NTFS_RECORD*)(kaddr +
152 i * rec_size), rec_size);
153 kunmap_atomic(kaddr);
154 local_irq_restore(flags);
155 flush_dcache_page(page);
156 if (likely(page_uptodate && !PageError(page)))
157 SetPageUptodate(page);
158 }
159 unlock_page(page);
160 return;
161still_busy:
162 bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
163 local_irq_restore(flags);
164 return;
165}
166
167/**
168 * ntfs_read_block - fill a @page of an address space with data
169 * @page: page cache page to fill with data
170 *
171 * Fill the page @page of the address space belonging to the @page->host inode.
172 * We read each buffer asynchronously and when all buffers are read in, our io
173 * completion handler ntfs_end_buffer_read_async(), if required, automatically
174 * applies the mst fixups to the page before finally marking it uptodate and
175 * unlocking it.
176 *
177 * We only enforce allocated_size limit because i_size is checked for in
178 * generic_file_read().
179 *
180 * Return 0 on success and -errno on error.
181 *
182 * Contains an adapted version of fs/buffer.c::block_read_full_page().
183 */
184static int ntfs_read_block(struct page *page)
185{
186 loff_t i_size;
187 VCN vcn;
188 LCN lcn;
189 s64 init_size;
190 struct inode *vi;
191 ntfs_inode *ni;
192 ntfs_volume *vol;
193 runlist_element *rl;
194 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
195 sector_t iblock, lblock, zblock;
196 unsigned long flags;
197 unsigned int blocksize, vcn_ofs;
198 int i, nr;
199 unsigned char blocksize_bits;
200
201 vi = page->mapping->host;
202 ni = NTFS_I(vi);
203 vol = ni->vol;
204
205 /* $MFT/$DATA must have its complete runlist in memory at all times. */
206 BUG_ON(!ni->runlist.rl && !ni->mft_no && !NInoAttr(ni));
207
208 blocksize = vol->sb->s_blocksize;
209 blocksize_bits = vol->sb->s_blocksize_bits;
210
211 if (!page_has_buffers(page)) {
212 create_empty_buffers(page, blocksize, 0);
213 if (unlikely(!page_has_buffers(page))) {
214 unlock_page(page);
215 return -ENOMEM;
216 }
217 }
218 bh = head = page_buffers(page);
219 BUG_ON(!bh);
220
221 /*
222 * We may be racing with truncate. To avoid some of the problems we
223 * now take a snapshot of the various sizes and use those for the whole
224 * of the function. In case of an extending truncate it just means we
225 * may leave some buffers unmapped which are now allocated. This is
226 * not a problem since these buffers will just get mapped when a write
227 * occurs. In case of a shrinking truncate, we will detect this later
228 * on due to the runlist being incomplete and if the page is being
229 * fully truncated, truncate will throw it away as soon as we unlock
230 * it so no need to worry what we do with it.
231 */
232 iblock = (s64)page->index << (PAGE_SHIFT - blocksize_bits);
233 read_lock_irqsave(&ni->size_lock, flags);
234 lblock = (ni->allocated_size + blocksize - 1) >> blocksize_bits;
235 init_size = ni->initialized_size;
236 i_size = i_size_read(vi);
237 read_unlock_irqrestore(&ni->size_lock, flags);
238 if (unlikely(init_size > i_size)) {
239 /* Race with shrinking truncate. */
240 init_size = i_size;
241 }
242 zblock = (init_size + blocksize - 1) >> blocksize_bits;
243
244 /* Loop through all the buffers in the page. */
245 rl = NULL;
246 nr = i = 0;
247 do {
248 int err = 0;
249
250 if (unlikely(buffer_uptodate(bh)))
251 continue;
252 if (unlikely(buffer_mapped(bh))) {
253 arr[nr++] = bh;
254 continue;
255 }
256 bh->b_bdev = vol->sb->s_bdev;
257 /* Is the block within the allowed limits? */
258 if (iblock < lblock) {
259 bool is_retry = false;
260
261 /* Convert iblock into corresponding vcn and offset. */
262 vcn = (VCN)iblock << blocksize_bits >>
263 vol->cluster_size_bits;
264 vcn_ofs = ((VCN)iblock << blocksize_bits) &
265 vol->cluster_size_mask;
266 if (!rl) {
267lock_retry_remap:
268 down_read(&ni->runlist.lock);
269 rl = ni->runlist.rl;
270 }
271 if (likely(rl != NULL)) {
272 /* Seek to element containing target vcn. */
273 while (rl->length && rl[1].vcn <= vcn)
274 rl++;
275 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
276 } else
277 lcn = LCN_RL_NOT_MAPPED;
278 /* Successful remap. */
279 if (lcn >= 0) {
280 /* Setup buffer head to correct block. */
281 bh->b_blocknr = ((lcn << vol->cluster_size_bits)
282 + vcn_ofs) >> blocksize_bits;
283 set_buffer_mapped(bh);
284 /* Only read initialized data blocks. */
285 if (iblock < zblock) {
286 arr[nr++] = bh;
287 continue;
288 }
289 /* Fully non-initialized data block, zero it. */
290 goto handle_zblock;
291 }
292 /* It is a hole, need to zero it. */
293 if (lcn == LCN_HOLE)
294 goto handle_hole;
295 /* If first try and runlist unmapped, map and retry. */
296 if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
297 is_retry = true;
298 /*
299 * Attempt to map runlist, dropping lock for
300 * the duration.
301 */
302 up_read(&ni->runlist.lock);
303 err = ntfs_map_runlist(ni, vcn);
304 if (likely(!err))
305 goto lock_retry_remap;
306 rl = NULL;
307 } else if (!rl)
308 up_read(&ni->runlist.lock);
309 /*
310 * If buffer is outside the runlist, treat it as a
311 * hole. This can happen due to concurrent truncate
312 * for example.
313 */
314 if (err == -ENOENT || lcn == LCN_ENOENT) {
315 err = 0;
316 goto handle_hole;
317 }
318 /* Hard error, zero out region. */
319 if (!err)
320 err = -EIO;
321 bh->b_blocknr = -1;
322 SetPageError(page);
323 ntfs_error(vol->sb, "Failed to read from inode 0x%lx, "
324 "attribute type 0x%x, vcn 0x%llx, "
325 "offset 0x%x because its location on "
326 "disk could not be determined%s "
327 "(error code %i).", ni->mft_no,
328 ni->type, (unsigned long long)vcn,
329 vcn_ofs, is_retry ? " even after "
330 "retrying" : "", err);
331 }
332 /*
333 * Either iblock was outside lblock limits or
334 * ntfs_rl_vcn_to_lcn() returned error. Just zero that portion
335 * of the page and set the buffer uptodate.
336 */
337handle_hole:
338 bh->b_blocknr = -1UL;
339 clear_buffer_mapped(bh);
340handle_zblock:
341 zero_user(page, i * blocksize, blocksize);
342 if (likely(!err))
343 set_buffer_uptodate(bh);
344 } while (i++, iblock++, (bh = bh->b_this_page) != head);
345
346 /* Release the lock if we took it. */
347 if (rl)
348 up_read(&ni->runlist.lock);
349
350 /* Check we have at least one buffer ready for i/o. */
351 if (nr) {
352 struct buffer_head *tbh;
353
354 /* Lock the buffers. */
355 for (i = 0; i < nr; i++) {
356 tbh = arr[i];
357 lock_buffer(tbh);
358 tbh->b_end_io = ntfs_end_buffer_async_read;
359 set_buffer_async_read(tbh);
360 }
361 /* Finally, start i/o on the buffers. */
362 for (i = 0; i < nr; i++) {
363 tbh = arr[i];
364 if (likely(!buffer_uptodate(tbh)))
365 submit_bh(READ, tbh);
366 else
367 ntfs_end_buffer_async_read(tbh, 1);
368 }
369 return 0;
370 }
371 /* No i/o was scheduled on any of the buffers. */
372 if (likely(!PageError(page)))
373 SetPageUptodate(page);
374 else /* Signal synchronous i/o error. */
375 nr = -EIO;
376 unlock_page(page);
377 return nr;
378}
379
380/**
381 * ntfs_readpage - fill a @page of a @file with data from the device
382 * @file: open file to which the page @page belongs or NULL
383 * @page: page cache page to fill with data
384 *
385 * For non-resident attributes, ntfs_readpage() fills the @page of the open
386 * file @file by calling the ntfs version of the generic block_read_full_page()
387 * function, ntfs_read_block(), which in turn creates and reads in the buffers
388 * associated with the page asynchronously.
389 *
390 * For resident attributes, OTOH, ntfs_readpage() fills @page by copying the
391 * data from the mft record (which at this stage is most likely in memory) and
392 * fills the remainder with zeroes. Thus, in this case, I/O is synchronous, as
393 * even if the mft record is not cached at this point in time, we need to wait
394 * for it to be read in before we can do the copy.
395 *
396 * Return 0 on success and -errno on error.
397 */
398static int ntfs_readpage(struct file *file, struct page *page)
399{
400 loff_t i_size;
401 struct inode *vi;
402 ntfs_inode *ni, *base_ni;
403 u8 *addr;
404 ntfs_attr_search_ctx *ctx;
405 MFT_RECORD *mrec;
406 unsigned long flags;
407 u32 attr_len;
408 int err = 0;
409
410retry_readpage:
411 BUG_ON(!PageLocked(page));
412 vi = page->mapping->host;
413 i_size = i_size_read(vi);
414 /* Is the page fully outside i_size? (truncate in progress) */
415 if (unlikely(page->index >= (i_size + PAGE_SIZE - 1) >>
416 PAGE_SHIFT)) {
417 zero_user(page, 0, PAGE_SIZE);
418 ntfs_debug("Read outside i_size - truncated?");
419 goto done;
420 }
421 /*
422 * This can potentially happen because we clear PageUptodate() during
423 * ntfs_writepage() of MstProtected() attributes.
424 */
425 if (PageUptodate(page)) {
426 unlock_page(page);
427 return 0;
428 }
429 ni = NTFS_I(vi);
430 /*
431 * Only $DATA attributes can be encrypted and only unnamed $DATA
432 * attributes can be compressed. Index root can have the flags set but
433 * this means to create compressed/encrypted files, not that the
434 * attribute is compressed/encrypted. Note we need to check for
435 * AT_INDEX_ALLOCATION since this is the type of both directory and
436 * index inodes.
437 */
438 if (ni->type != AT_INDEX_ALLOCATION) {
439 /* If attribute is encrypted, deny access, just like NT4. */
440 if (NInoEncrypted(ni)) {
441 BUG_ON(ni->type != AT_DATA);
442 err = -EACCES;
443 goto err_out;
444 }
445 /* Compressed data streams are handled in compress.c. */
446 if (NInoNonResident(ni) && NInoCompressed(ni)) {
447 BUG_ON(ni->type != AT_DATA);
448 BUG_ON(ni->name_len);
449 return ntfs_read_compressed_block(page);
450 }
451 }
452 /* NInoNonResident() == NInoIndexAllocPresent() */
453 if (NInoNonResident(ni)) {
454 /* Normal, non-resident data stream. */
455 return ntfs_read_block(page);
456 }
457 /*
458 * Attribute is resident, implying it is not compressed or encrypted.
459 * This also means the attribute is smaller than an mft record and
460 * hence smaller than a page, so can simply zero out any pages with
461 * index above 0. Note the attribute can actually be marked compressed
462 * but if it is resident the actual data is not compressed so we are
463 * ok to ignore the compressed flag here.
464 */
465 if (unlikely(page->index > 0)) {
466 zero_user(page, 0, PAGE_SIZE);
467 goto done;
468 }
469 if (!NInoAttr(ni))
470 base_ni = ni;
471 else
472 base_ni = ni->ext.base_ntfs_ino;
473 /* Map, pin, and lock the mft record. */
474 mrec = map_mft_record(base_ni);
475 if (IS_ERR(mrec)) {
476 err = PTR_ERR(mrec);
477 goto err_out;
478 }
479 /*
480 * If a parallel write made the attribute non-resident, drop the mft
481 * record and retry the readpage.
482 */
483 if (unlikely(NInoNonResident(ni))) {
484 unmap_mft_record(base_ni);
485 goto retry_readpage;
486 }
487 ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
488 if (unlikely(!ctx)) {
489 err = -ENOMEM;
490 goto unm_err_out;
491 }
492 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
493 CASE_SENSITIVE, 0, NULL, 0, ctx);
494 if (unlikely(err))
495 goto put_unm_err_out;
496 attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
497 read_lock_irqsave(&ni->size_lock, flags);
498 if (unlikely(attr_len > ni->initialized_size))
499 attr_len = ni->initialized_size;
500 i_size = i_size_read(vi);
501 read_unlock_irqrestore(&ni->size_lock, flags);
502 if (unlikely(attr_len > i_size)) {
503 /* Race with shrinking truncate. */
504 attr_len = i_size;
505 }
506 addr = kmap_atomic(page);
507 /* Copy the data to the page. */
508 memcpy(addr, (u8*)ctx->attr +
509 le16_to_cpu(ctx->attr->data.resident.value_offset),
510 attr_len);
511 /* Zero the remainder of the page. */
512 memset(addr + attr_len, 0, PAGE_SIZE - attr_len);
513 flush_dcache_page(page);
514 kunmap_atomic(addr);
515put_unm_err_out:
516 ntfs_attr_put_search_ctx(ctx);
517unm_err_out:
518 unmap_mft_record(base_ni);
519done:
520 SetPageUptodate(page);
521err_out:
522 unlock_page(page);
523 return err;
524}
525
526#ifdef NTFS_RW
527
528/**
529 * ntfs_write_block - write a @page to the backing store
530 * @page: page cache page to write out
531 * @wbc: writeback control structure
532 *
533 * This function is for writing pages belonging to non-resident, non-mst
534 * protected attributes to their backing store.
535 *
536 * For a page with buffers, map and write the dirty buffers asynchronously
537 * under page writeback. For a page without buffers, create buffers for the
538 * page, then proceed as above.
539 *
540 * If a page doesn't have buffers the page dirty state is definitive. If a page
541 * does have buffers, the page dirty state is just a hint, and the buffer dirty
542 * state is definitive. (A hint which has rules: dirty buffers against a clean
543 * page is illegal. Other combinations are legal and need to be handled. In
544 * particular a dirty page containing clean buffers for example.)
545 *
546 * Return 0 on success and -errno on error.
547 *
548 * Based on ntfs_read_block() and __block_write_full_page().
549 */
550static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
551{
552 VCN vcn;
553 LCN lcn;
554 s64 initialized_size;
555 loff_t i_size;
556 sector_t block, dblock, iblock;
557 struct inode *vi;
558 ntfs_inode *ni;
559 ntfs_volume *vol;
560 runlist_element *rl;
561 struct buffer_head *bh, *head;
562 unsigned long flags;
563 unsigned int blocksize, vcn_ofs;
564 int err;
565 bool need_end_writeback;
566 unsigned char blocksize_bits;
567
568 vi = page->mapping->host;
569 ni = NTFS_I(vi);
570 vol = ni->vol;
571
572 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
573 "0x%lx.", ni->mft_no, ni->type, page->index);
574
575 BUG_ON(!NInoNonResident(ni));
576 BUG_ON(NInoMstProtected(ni));
577 blocksize = vol->sb->s_blocksize;
578 blocksize_bits = vol->sb->s_blocksize_bits;
579 if (!page_has_buffers(page)) {
580 BUG_ON(!PageUptodate(page));
581 create_empty_buffers(page, blocksize,
582 (1 << BH_Uptodate) | (1 << BH_Dirty));
583 if (unlikely(!page_has_buffers(page))) {
584 ntfs_warning(vol->sb, "Error allocating page "
585 "buffers. Redirtying page so we try "
586 "again later.");
587 /*
588 * Put the page back on mapping->dirty_pages, but leave
589 * its buffers' dirty state as-is.
590 */
591 redirty_page_for_writepage(wbc, page);
592 unlock_page(page);
593 return 0;
594 }
595 }
596 bh = head = page_buffers(page);
597 BUG_ON(!bh);
598
599 /* NOTE: Different naming scheme to ntfs_read_block()! */
600
601 /* The first block in the page. */
602 block = (s64)page->index << (PAGE_SHIFT - blocksize_bits);
603
604 read_lock_irqsave(&ni->size_lock, flags);
605 i_size = i_size_read(vi);
606 initialized_size = ni->initialized_size;
607 read_unlock_irqrestore(&ni->size_lock, flags);
608
609 /* The first out of bounds block for the data size. */
610 dblock = (i_size + blocksize - 1) >> blocksize_bits;
611
612 /* The last (fully or partially) initialized block. */
613 iblock = initialized_size >> blocksize_bits;
614
615 /*
616 * Be very careful. We have no exclusion from __set_page_dirty_buffers
617 * here, and the (potentially unmapped) buffers may become dirty at
618 * any time. If a buffer becomes dirty here after we've inspected it
619 * then we just miss that fact, and the page stays dirty.
620 *
621 * Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
622 * handle that here by just cleaning them.
623 */
624
625 /*
626 * Loop through all the buffers in the page, mapping all the dirty
627 * buffers to disk addresses and handling any aliases from the
628 * underlying block device's mapping.
629 */
630 rl = NULL;
631 err = 0;
632 do {
633 bool is_retry = false;
634
635 if (unlikely(block >= dblock)) {
636 /*
637 * Mapped buffers outside i_size will occur, because
638 * this page can be outside i_size when there is a
639 * truncate in progress. The contents of such buffers
640 * were zeroed by ntfs_writepage().
641 *
642 * FIXME: What about the small race window where
643 * ntfs_writepage() has not done any clearing because
644 * the page was within i_size but before we get here,
645 * vmtruncate() modifies i_size?
646 */
647 clear_buffer_dirty(bh);
648 set_buffer_uptodate(bh);
649 continue;
650 }
651
652 /* Clean buffers are not written out, so no need to map them. */
653 if (!buffer_dirty(bh))
654 continue;
655
656 /* Make sure we have enough initialized size. */
657 if (unlikely((block >= iblock) &&
658 (initialized_size < i_size))) {
659 /*
660 * If this page is fully outside initialized size, zero
661 * out all pages between the current initialized size
662 * and the current page. Just use ntfs_readpage() to do
663 * the zeroing transparently.
664 */
665 if (block > iblock) {
666 // TODO:
667 // For each page do:
668 // - read_cache_page()
669 // Again for each page do:
670 // - wait_on_page_locked()
671 // - Check (PageUptodate(page) &&
672 // !PageError(page))
673 // Update initialized size in the attribute and
674 // in the inode.
675 // Again, for each page do:
676 // __set_page_dirty_buffers();
677 // put_page()
678 // We don't need to wait on the writes.
679 // Update iblock.
680 }
681 /*
682 * The current page straddles initialized size. Zero
683 * all non-uptodate buffers and set them uptodate (and
684 * dirty?). Note, there aren't any non-uptodate buffers
685 * if the page is uptodate.
686 * FIXME: For an uptodate page, the buffers may need to
687 * be written out because they were not initialized on
688 * disk before.
689 */
690 if (!PageUptodate(page)) {
691 // TODO:
692 // Zero any non-uptodate buffers up to i_size.
693 // Set them uptodate and dirty.
694 }
695 // TODO:
696 // Update initialized size in the attribute and in the
697 // inode (up to i_size).
698 // Update iblock.
699 // FIXME: This is inefficient. Try to batch the two
700 // size changes to happen in one go.
701 ntfs_error(vol->sb, "Writing beyond initialized size "
702 "is not supported yet. Sorry.");
703 err = -EOPNOTSUPP;
704 break;
705 // Do NOT set_buffer_new() BUT DO clear buffer range
706 // outside write request range.
707 // set_buffer_uptodate() on complete buffers as well as
708 // set_buffer_dirty().
709 }
710
711 /* No need to map buffers that are already mapped. */
712 if (buffer_mapped(bh))
713 continue;
714
715 /* Unmapped, dirty buffer. Need to map it. */
716 bh->b_bdev = vol->sb->s_bdev;
717
718 /* Convert block into corresponding vcn and offset. */
719 vcn = (VCN)block << blocksize_bits;
720 vcn_ofs = vcn & vol->cluster_size_mask;
721 vcn >>= vol->cluster_size_bits;
722 if (!rl) {
723lock_retry_remap:
724 down_read(&ni->runlist.lock);
725 rl = ni->runlist.rl;
726 }
727 if (likely(rl != NULL)) {
728 /* Seek to element containing target vcn. */
729 while (rl->length && rl[1].vcn <= vcn)
730 rl++;
731 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
732 } else
733 lcn = LCN_RL_NOT_MAPPED;
734 /* Successful remap. */
735 if (lcn >= 0) {
736 /* Setup buffer head to point to correct block. */
737 bh->b_blocknr = ((lcn << vol->cluster_size_bits) +
738 vcn_ofs) >> blocksize_bits;
739 set_buffer_mapped(bh);
740 continue;
741 }
742 /* It is a hole, need to instantiate it. */
743 if (lcn == LCN_HOLE) {
744 u8 *kaddr;
745 unsigned long *bpos, *bend;
746
747 /* Check if the buffer is zero. */
748 kaddr = kmap_atomic(page);
749 bpos = (unsigned long *)(kaddr + bh_offset(bh));
750 bend = (unsigned long *)((u8*)bpos + blocksize);
751 do {
752 if (unlikely(*bpos))
753 break;
754 } while (likely(++bpos < bend));
755 kunmap_atomic(kaddr);
756 if (bpos == bend) {
757 /*
758 * Buffer is zero and sparse, no need to write
759 * it.
760 */
761 bh->b_blocknr = -1;
762 clear_buffer_dirty(bh);
763 continue;
764 }
765 // TODO: Instantiate the hole.
766 // clear_buffer_new(bh);
767 // unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
768 ntfs_error(vol->sb, "Writing into sparse regions is "
769 "not supported yet. Sorry.");
770 err = -EOPNOTSUPP;
771 break;
772 }
773 /* If first try and runlist unmapped, map and retry. */
774 if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
775 is_retry = true;
776 /*
777 * Attempt to map runlist, dropping lock for
778 * the duration.
779 */
780 up_read(&ni->runlist.lock);
781 err = ntfs_map_runlist(ni, vcn);
782 if (likely(!err))
783 goto lock_retry_remap;
784 rl = NULL;
785 } else if (!rl)
786 up_read(&ni->runlist.lock);
787 /*
788 * If buffer is outside the runlist, truncate has cut it out
789 * of the runlist. Just clean and clear the buffer and set it
790 * uptodate so it can get discarded by the VM.
791 */
792 if (err == -ENOENT || lcn == LCN_ENOENT) {
793 bh->b_blocknr = -1;
794 clear_buffer_dirty(bh);
795 zero_user(page, bh_offset(bh), blocksize);
796 set_buffer_uptodate(bh);
797 err = 0;
798 continue;
799 }
800 /* Failed to map the buffer, even after retrying. */
801 if (!err)
802 err = -EIO;
803 bh->b_blocknr = -1;
804 ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
805 "attribute type 0x%x, vcn 0x%llx, offset 0x%x "
806 "because its location on disk could not be "
807 "determined%s (error code %i).", ni->mft_no,
808 ni->type, (unsigned long long)vcn,
809 vcn_ofs, is_retry ? " even after "
810 "retrying" : "", err);
811 break;
812 } while (block++, (bh = bh->b_this_page) != head);
813
814 /* Release the lock if we took it. */
815 if (rl)
816 up_read(&ni->runlist.lock);
817
818 /* For the error case, need to reset bh to the beginning. */
819 bh = head;
820
821 /* Just an optimization, so ->readpage() is not called later. */
822 if (unlikely(!PageUptodate(page))) {
823 int uptodate = 1;
824 do {
825 if (!buffer_uptodate(bh)) {
826 uptodate = 0;
827 bh = head;
828 break;
829 }
830 } while ((bh = bh->b_this_page) != head);
831 if (uptodate)
832 SetPageUptodate(page);
833 }
834
835 /* Setup all mapped, dirty buffers for async write i/o. */
836 do {
837 if (buffer_mapped(bh) && buffer_dirty(bh)) {
838 lock_buffer(bh);
839 if (test_clear_buffer_dirty(bh)) {
840 BUG_ON(!buffer_uptodate(bh));
841 mark_buffer_async_write(bh);
842 } else
843 unlock_buffer(bh);
844 } else if (unlikely(err)) {
845 /*
846 * For the error case. The buffer may have been set
847 * dirty during attachment to a dirty page.
848 */
849 if (err != -ENOMEM)
850 clear_buffer_dirty(bh);
851 }
852 } while ((bh = bh->b_this_page) != head);
853
854 if (unlikely(err)) {
855 // TODO: Remove the -EOPNOTSUPP check later on...
856 if (unlikely(err == -EOPNOTSUPP))
857 err = 0;
858 else if (err == -ENOMEM) {
859 ntfs_warning(vol->sb, "Error allocating memory. "
860 "Redirtying page so we try again "
861 "later.");
862 /*
863 * Put the page back on mapping->dirty_pages, but
864 * leave its buffer's dirty state as-is.
865 */
866 redirty_page_for_writepage(wbc, page);
867 err = 0;
868 } else
869 SetPageError(page);
870 }
871
872 BUG_ON(PageWriteback(page));
873 set_page_writeback(page); /* Keeps try_to_free_buffers() away. */
874
875 /* Submit the prepared buffers for i/o. */
876 need_end_writeback = true;
877 do {
878 struct buffer_head *next = bh->b_this_page;
879 if (buffer_async_write(bh)) {
880 submit_bh(WRITE, bh);
881 need_end_writeback = false;
882 }
883 bh = next;
884 } while (bh != head);
885 unlock_page(page);
886
887 /* If no i/o was started, need to end_page_writeback(). */
888 if (unlikely(need_end_writeback))
889 end_page_writeback(page);
890
891 ntfs_debug("Done.");
892 return err;
893}
894
895/**
896 * ntfs_write_mst_block - write a @page to the backing store
897 * @page: page cache page to write out
898 * @wbc: writeback control structure
899 *
900 * This function is for writing pages belonging to non-resident, mst protected
901 * attributes to their backing store. The only supported attributes are index
902 * allocation and $MFT/$DATA. Both directory inodes and index inodes are
903 * supported for the index allocation case.
904 *
905 * The page must remain locked for the duration of the write because we apply
906 * the mst fixups, write, and then undo the fixups, so if we were to unlock the
907 * page before undoing the fixups, any other user of the page will see the
908 * page contents as corrupt.
909 *
910 * We clear the page uptodate flag for the duration of the function to ensure
911 * exclusion for the $MFT/$DATA case against someone mapping an mft record we
912 * are about to apply the mst fixups to.
913 *
914 * Return 0 on success and -errno on error.
915 *
916 * Based on ntfs_write_block(), ntfs_mft_writepage(), and
917 * write_mft_record_nolock().
918 */
919static int ntfs_write_mst_block(struct page *page,
920 struct writeback_control *wbc)
921{
922 sector_t block, dblock, rec_block;
923 struct inode *vi = page->mapping->host;
924 ntfs_inode *ni = NTFS_I(vi);
925 ntfs_volume *vol = ni->vol;
926 u8 *kaddr;
927 unsigned int rec_size = ni->itype.index.block_size;
928 ntfs_inode *locked_nis[PAGE_SIZE / rec_size];
929 struct buffer_head *bh, *head, *tbh, *rec_start_bh;
930 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
931 runlist_element *rl;
932 int i, nr_locked_nis, nr_recs, nr_bhs, max_bhs, bhs_per_rec, err, err2;
933 unsigned bh_size, rec_size_bits;
934 bool sync, is_mft, page_is_dirty, rec_is_dirty;
935 unsigned char bh_size_bits;
936
937 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
938 "0x%lx.", vi->i_ino, ni->type, page->index);
939 BUG_ON(!NInoNonResident(ni));
940 BUG_ON(!NInoMstProtected(ni));
941 is_mft = (S_ISREG(vi->i_mode) && !vi->i_ino);
942 /*
943 * NOTE: ntfs_write_mst_block() would be called for $MFTMirr if a page
944 * in its page cache were to be marked dirty. However this should
945 * never happen with the current driver and considering we do not
946 * handle this case here we do want to BUG(), at least for now.
947 */
948 BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
949 (NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
950 bh_size = vol->sb->s_blocksize;
951 bh_size_bits = vol->sb->s_blocksize_bits;
952 max_bhs = PAGE_SIZE / bh_size;
953 BUG_ON(!max_bhs);
954 BUG_ON(max_bhs > MAX_BUF_PER_PAGE);
955
956 /* Were we called for sync purposes? */
957 sync = (wbc->sync_mode == WB_SYNC_ALL);
958
959 /* Make sure we have mapped buffers. */
960 bh = head = page_buffers(page);
961 BUG_ON(!bh);
962
963 rec_size_bits = ni->itype.index.block_size_bits;
964 BUG_ON(!(PAGE_SIZE >> rec_size_bits));
965 bhs_per_rec = rec_size >> bh_size_bits;
966 BUG_ON(!bhs_per_rec);
967
968 /* The first block in the page. */
969 rec_block = block = (sector_t)page->index <<
970 (PAGE_SHIFT - bh_size_bits);
971
972 /* The first out of bounds block for the data size. */
973 dblock = (i_size_read(vi) + bh_size - 1) >> bh_size_bits;
974
975 rl = NULL;
976 err = err2 = nr_bhs = nr_recs = nr_locked_nis = 0;
977 page_is_dirty = rec_is_dirty = false;
978 rec_start_bh = NULL;
979 do {
980 bool is_retry = false;
981
982 if (likely(block < rec_block)) {
983 if (unlikely(block >= dblock)) {
984 clear_buffer_dirty(bh);
985 set_buffer_uptodate(bh);
986 continue;
987 }
988 /*
989 * This block is not the first one in the record. We
990 * ignore the buffer's dirty state because we could
991 * have raced with a parallel mark_ntfs_record_dirty().
992 */
993 if (!rec_is_dirty)
994 continue;
995 if (unlikely(err2)) {
996 if (err2 != -ENOMEM)
997 clear_buffer_dirty(bh);
998 continue;
999 }
1000 } else /* if (block == rec_block) */ {
1001 BUG_ON(block > rec_block);
1002 /* This block is the first one in the record. */
1003 rec_block += bhs_per_rec;
1004 err2 = 0;
1005 if (unlikely(block >= dblock)) {
1006 clear_buffer_dirty(bh);
1007 continue;
1008 }
1009 if (!buffer_dirty(bh)) {
1010 /* Clean records are not written out. */
1011 rec_is_dirty = false;
1012 continue;
1013 }
1014 rec_is_dirty = true;
1015 rec_start_bh = bh;
1016 }
1017 /* Need to map the buffer if it is not mapped already. */
1018 if (unlikely(!buffer_mapped(bh))) {
1019 VCN vcn;
1020 LCN lcn;
1021 unsigned int vcn_ofs;
1022
1023 bh->b_bdev = vol->sb->s_bdev;
1024 /* Obtain the vcn and offset of the current block. */
1025 vcn = (VCN)block << bh_size_bits;
1026 vcn_ofs = vcn & vol->cluster_size_mask;
1027 vcn >>= vol->cluster_size_bits;
1028 if (!rl) {
1029lock_retry_remap:
1030 down_read(&ni->runlist.lock);
1031 rl = ni->runlist.rl;
1032 }
1033 if (likely(rl != NULL)) {
1034 /* Seek to element containing target vcn. */
1035 while (rl->length && rl[1].vcn <= vcn)
1036 rl++;
1037 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
1038 } else
1039 lcn = LCN_RL_NOT_MAPPED;
1040 /* Successful remap. */
1041 if (likely(lcn >= 0)) {
1042 /* Setup buffer head to correct block. */
1043 bh->b_blocknr = ((lcn <<
1044 vol->cluster_size_bits) +
1045 vcn_ofs) >> bh_size_bits;
1046 set_buffer_mapped(bh);
1047 } else {
1048 /*
1049 * Remap failed. Retry to map the runlist once
1050 * unless we are working on $MFT which always
1051 * has the whole of its runlist in memory.
1052 */
1053 if (!is_mft && !is_retry &&
1054 lcn == LCN_RL_NOT_MAPPED) {
1055 is_retry = true;
1056 /*
1057 * Attempt to map runlist, dropping
1058 * lock for the duration.
1059 */
1060 up_read(&ni->runlist.lock);
1061 err2 = ntfs_map_runlist(ni, vcn);
1062 if (likely(!err2))
1063 goto lock_retry_remap;
1064 if (err2 == -ENOMEM)
1065 page_is_dirty = true;
1066 lcn = err2;
1067 } else {
1068 err2 = -EIO;
1069 if (!rl)
1070 up_read(&ni->runlist.lock);
1071 }
1072 /* Hard error. Abort writing this record. */
1073 if (!err || err == -ENOMEM)
1074 err = err2;
1075 bh->b_blocknr = -1;
1076 ntfs_error(vol->sb, "Cannot write ntfs record "
1077 "0x%llx (inode 0x%lx, "
1078 "attribute type 0x%x) because "
1079 "its location on disk could "
1080 "not be determined (error "
1081 "code %lli).",
1082 (long long)block <<
1083 bh_size_bits >>
1084 vol->mft_record_size_bits,
1085 ni->mft_no, ni->type,
1086 (long long)lcn);
1087 /*
1088 * If this is not the first buffer, remove the
1089 * buffers in this record from the list of
1090 * buffers to write and clear their dirty bit
1091 * if not error -ENOMEM.
1092 */
1093 if (rec_start_bh != bh) {
1094 while (bhs[--nr_bhs] != rec_start_bh)
1095 ;
1096 if (err2 != -ENOMEM) {
1097 do {
1098 clear_buffer_dirty(
1099 rec_start_bh);
1100 } while ((rec_start_bh =
1101 rec_start_bh->
1102 b_this_page) !=
1103 bh);
1104 }
1105 }
1106 continue;
1107 }
1108 }
1109 BUG_ON(!buffer_uptodate(bh));
1110 BUG_ON(nr_bhs >= max_bhs);
1111 bhs[nr_bhs++] = bh;
1112 } while (block++, (bh = bh->b_this_page) != head);
1113 if (unlikely(rl))
1114 up_read(&ni->runlist.lock);
1115 /* If there were no dirty buffers, we are done. */
1116 if (!nr_bhs)
1117 goto done;
1118 /* Map the page so we can access its contents. */
1119 kaddr = kmap(page);
1120 /* Clear the page uptodate flag whilst the mst fixups are applied. */
1121 BUG_ON(!PageUptodate(page));
1122 ClearPageUptodate(page);
1123 for (i = 0; i < nr_bhs; i++) {
1124 unsigned int ofs;
1125
1126 /* Skip buffers which are not at the beginning of records. */
1127 if (i % bhs_per_rec)
1128 continue;
1129 tbh = bhs[i];
1130 ofs = bh_offset(tbh);
1131 if (is_mft) {
1132 ntfs_inode *tni;
1133 unsigned long mft_no;
1134
1135 /* Get the mft record number. */
1136 mft_no = (((s64)page->index << PAGE_SHIFT) + ofs)
1137 >> rec_size_bits;
1138 /* Check whether to write this mft record. */
1139 tni = NULL;
1140 if (!ntfs_may_write_mft_record(vol, mft_no,
1141 (MFT_RECORD*)(kaddr + ofs), &tni)) {
1142 /*
1143 * The record should not be written. This
1144 * means we need to redirty the page before
1145 * returning.
1146 */
1147 page_is_dirty = true;
1148 /*
1149 * Remove the buffers in this mft record from
1150 * the list of buffers to write.
1151 */
1152 do {
1153 bhs[i] = NULL;
1154 } while (++i % bhs_per_rec);
1155 continue;
1156 }
1157 /*
1158 * The record should be written. If a locked ntfs
1159 * inode was returned, add it to the array of locked
1160 * ntfs inodes.
1161 */
1162 if (tni)
1163 locked_nis[nr_locked_nis++] = tni;
1164 }
1165 /* Apply the mst protection fixups. */
1166 err2 = pre_write_mst_fixup((NTFS_RECORD*)(kaddr + ofs),
1167 rec_size);
1168 if (unlikely(err2)) {
1169 if (!err || err == -ENOMEM)
1170 err = -EIO;
1171 ntfs_error(vol->sb, "Failed to apply mst fixups "
1172 "(inode 0x%lx, attribute type 0x%x, "
1173 "page index 0x%lx, page offset 0x%x)!"
1174 " Unmount and run chkdsk.", vi->i_ino,
1175 ni->type, page->index, ofs);
1176 /*
1177 * Mark all the buffers in this record clean as we do
1178 * not want to write corrupt data to disk.
1179 */
1180 do {
1181 clear_buffer_dirty(bhs[i]);
1182 bhs[i] = NULL;
1183 } while (++i % bhs_per_rec);
1184 continue;
1185 }
1186 nr_recs++;
1187 }
1188 /* If no records are to be written out, we are done. */
1189 if (!nr_recs)
1190 goto unm_done;
1191 flush_dcache_page(page);
1192 /* Lock buffers and start synchronous write i/o on them. */
1193 for (i = 0; i < nr_bhs; i++) {
1194 tbh = bhs[i];
1195 if (!tbh)
1196 continue;
1197 if (!trylock_buffer(tbh))
1198 BUG();
1199 /* The buffer dirty state is now irrelevant, just clean it. */
1200 clear_buffer_dirty(tbh);
1201 BUG_ON(!buffer_uptodate(tbh));
1202 BUG_ON(!buffer_mapped(tbh));
1203 get_bh(tbh);
1204 tbh->b_end_io = end_buffer_write_sync;
1205 submit_bh(WRITE, tbh);
1206 }
1207 /* Synchronize the mft mirror now if not @sync. */
1208 if (is_mft && !sync)
1209 goto do_mirror;
1210do_wait:
1211 /* Wait on i/o completion of buffers. */
1212 for (i = 0; i < nr_bhs; i++) {
1213 tbh = bhs[i];
1214 if (!tbh)
1215 continue;
1216 wait_on_buffer(tbh);
1217 if (unlikely(!buffer_uptodate(tbh))) {
1218 ntfs_error(vol->sb, "I/O error while writing ntfs "
1219 "record buffer (inode 0x%lx, "
1220 "attribute type 0x%x, page index "
1221 "0x%lx, page offset 0x%lx)! Unmount "
1222 "and run chkdsk.", vi->i_ino, ni->type,
1223 page->index, bh_offset(tbh));
1224 if (!err || err == -ENOMEM)
1225 err = -EIO;
1226 /*
1227 * Set the buffer uptodate so the page and buffer
1228 * states do not become out of sync.
1229 */
1230 set_buffer_uptodate(tbh);
1231 }
1232 }
1233 /* If @sync, now synchronize the mft mirror. */
1234 if (is_mft && sync) {
1235do_mirror:
1236 for (i = 0; i < nr_bhs; i++) {
1237 unsigned long mft_no;
1238 unsigned int ofs;
1239
1240 /*
1241 * Skip buffers which are not at the beginning of
1242 * records.
1243 */
1244 if (i % bhs_per_rec)
1245 continue;
1246 tbh = bhs[i];
1247 /* Skip removed buffers (and hence records). */
1248 if (!tbh)
1249 continue;
1250 ofs = bh_offset(tbh);
1251 /* Get the mft record number. */
1252 mft_no = (((s64)page->index << PAGE_SHIFT) + ofs)
1253 >> rec_size_bits;
1254 if (mft_no < vol->mftmirr_size)
1255 ntfs_sync_mft_mirror(vol, mft_no,
1256 (MFT_RECORD*)(kaddr + ofs),
1257 sync);
1258 }
1259 if (!sync)
1260 goto do_wait;
1261 }
1262 /* Remove the mst protection fixups again. */
1263 for (i = 0; i < nr_bhs; i++) {
1264 if (!(i % bhs_per_rec)) {
1265 tbh = bhs[i];
1266 if (!tbh)
1267 continue;
1268 post_write_mst_fixup((NTFS_RECORD*)(kaddr +
1269 bh_offset(tbh)));
1270 }
1271 }
1272 flush_dcache_page(page);
1273unm_done:
1274 /* Unlock any locked inodes. */
1275 while (nr_locked_nis-- > 0) {
1276 ntfs_inode *tni, *base_tni;
1277
1278 tni = locked_nis[nr_locked_nis];
1279 /* Get the base inode. */
1280 mutex_lock(&tni->extent_lock);
1281 if (tni->nr_extents >= 0)
1282 base_tni = tni;
1283 else {
1284 base_tni = tni->ext.base_ntfs_ino;
1285 BUG_ON(!base_tni);
1286 }
1287 mutex_unlock(&tni->extent_lock);
1288 ntfs_debug("Unlocking %s inode 0x%lx.",
1289 tni == base_tni ? "base" : "extent",
1290 tni->mft_no);
1291 mutex_unlock(&tni->mrec_lock);
1292 atomic_dec(&tni->count);
1293 iput(VFS_I(base_tni));
1294 }
1295 SetPageUptodate(page);
1296 kunmap(page);
1297done:
1298 if (unlikely(err && err != -ENOMEM)) {
1299 /*
1300 * Set page error if there is only one ntfs record in the page.
1301 * Otherwise we would loose per-record granularity.
1302 */
1303 if (ni->itype.index.block_size == PAGE_SIZE)
1304 SetPageError(page);
1305 NVolSetErrors(vol);
1306 }
1307 if (page_is_dirty) {
1308 ntfs_debug("Page still contains one or more dirty ntfs "
1309 "records. Redirtying the page starting at "
1310 "record 0x%lx.", page->index <<
1311 (PAGE_SHIFT - rec_size_bits));
1312 redirty_page_for_writepage(wbc, page);
1313 unlock_page(page);
1314 } else {
1315 /*
1316 * Keep the VM happy. This must be done otherwise the
1317 * radix-tree tag PAGECACHE_TAG_DIRTY remains set even though
1318 * the page is clean.
1319 */
1320 BUG_ON(PageWriteback(page));
1321 set_page_writeback(page);
1322 unlock_page(page);
1323 end_page_writeback(page);
1324 }
1325 if (likely(!err))
1326 ntfs_debug("Done.");
1327 return err;
1328}
1329
1330/**
1331 * ntfs_writepage - write a @page to the backing store
1332 * @page: page cache page to write out
1333 * @wbc: writeback control structure
1334 *
1335 * This is called from the VM when it wants to have a dirty ntfs page cache
1336 * page cleaned. The VM has already locked the page and marked it clean.
1337 *
1338 * For non-resident attributes, ntfs_writepage() writes the @page by calling
1339 * the ntfs version of the generic block_write_full_page() function,
1340 * ntfs_write_block(), which in turn if necessary creates and writes the
1341 * buffers associated with the page asynchronously.
1342 *
1343 * For resident attributes, OTOH, ntfs_writepage() writes the @page by copying
1344 * the data to the mft record (which at this stage is most likely in memory).
1345 * The mft record is then marked dirty and written out asynchronously via the
1346 * vfs inode dirty code path for the inode the mft record belongs to or via the
1347 * vm page dirty code path for the page the mft record is in.
1348 *
1349 * Based on ntfs_readpage() and fs/buffer.c::block_write_full_page().
1350 *
1351 * Return 0 on success and -errno on error.
1352 */
1353static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
1354{
1355 loff_t i_size;
1356 struct inode *vi = page->mapping->host;
1357 ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
1358 char *addr;
1359 ntfs_attr_search_ctx *ctx = NULL;
1360 MFT_RECORD *m = NULL;
1361 u32 attr_len;
1362 int err;
1363
1364retry_writepage:
1365 BUG_ON(!PageLocked(page));
1366 i_size = i_size_read(vi);
1367 /* Is the page fully outside i_size? (truncate in progress) */
1368 if (unlikely(page->index >= (i_size + PAGE_SIZE - 1) >>
1369 PAGE_SHIFT)) {
1370 /*
1371 * The page may have dirty, unmapped buffers. Make them
1372 * freeable here, so the page does not leak.
1373 */
1374 block_invalidatepage(page, 0, PAGE_SIZE);
1375 unlock_page(page);
1376 ntfs_debug("Write outside i_size - truncated?");
1377 return 0;
1378 }
1379 /*
1380 * Only $DATA attributes can be encrypted and only unnamed $DATA
1381 * attributes can be compressed. Index root can have the flags set but
1382 * this means to create compressed/encrypted files, not that the
1383 * attribute is compressed/encrypted. Note we need to check for
1384 * AT_INDEX_ALLOCATION since this is the type of both directory and
1385 * index inodes.
1386 */
1387 if (ni->type != AT_INDEX_ALLOCATION) {
1388 /* If file is encrypted, deny access, just like NT4. */
1389 if (NInoEncrypted(ni)) {
1390 unlock_page(page);
1391 BUG_ON(ni->type != AT_DATA);
1392 ntfs_debug("Denying write access to encrypted file.");
1393 return -EACCES;
1394 }
1395 /* Compressed data streams are handled in compress.c. */
1396 if (NInoNonResident(ni) && NInoCompressed(ni)) {
1397 BUG_ON(ni->type != AT_DATA);
1398 BUG_ON(ni->name_len);
1399 // TODO: Implement and replace this with
1400 // return ntfs_write_compressed_block(page);
1401 unlock_page(page);
1402 ntfs_error(vi->i_sb, "Writing to compressed files is "
1403 "not supported yet. Sorry.");
1404 return -EOPNOTSUPP;
1405 }
1406 // TODO: Implement and remove this check.
1407 if (NInoNonResident(ni) && NInoSparse(ni)) {
1408 unlock_page(page);
1409 ntfs_error(vi->i_sb, "Writing to sparse files is not "
1410 "supported yet. Sorry.");
1411 return -EOPNOTSUPP;
1412 }
1413 }
1414 /* NInoNonResident() == NInoIndexAllocPresent() */
1415 if (NInoNonResident(ni)) {
1416 /* We have to zero every time due to mmap-at-end-of-file. */
1417 if (page->index >= (i_size >> PAGE_SHIFT)) {
1418 /* The page straddles i_size. */
1419 unsigned int ofs = i_size & ~PAGE_MASK;
1420 zero_user_segment(page, ofs, PAGE_SIZE);
1421 }
1422 /* Handle mst protected attributes. */
1423 if (NInoMstProtected(ni))
1424 return ntfs_write_mst_block(page, wbc);
1425 /* Normal, non-resident data stream. */
1426 return ntfs_write_block(page, wbc);
1427 }
1428 /*
1429 * Attribute is resident, implying it is not compressed, encrypted, or
1430 * mst protected. This also means the attribute is smaller than an mft
1431 * record and hence smaller than a page, so can simply return error on
1432 * any pages with index above 0. Note the attribute can actually be
1433 * marked compressed but if it is resident the actual data is not
1434 * compressed so we are ok to ignore the compressed flag here.
1435 */
1436 BUG_ON(page_has_buffers(page));
1437 BUG_ON(!PageUptodate(page));
1438 if (unlikely(page->index > 0)) {
1439 ntfs_error(vi->i_sb, "BUG()! page->index (0x%lx) > 0. "
1440 "Aborting write.", page->index);
1441 BUG_ON(PageWriteback(page));
1442 set_page_writeback(page);
1443 unlock_page(page);
1444 end_page_writeback(page);
1445 return -EIO;
1446 }
1447 if (!NInoAttr(ni))
1448 base_ni = ni;
1449 else
1450 base_ni = ni->ext.base_ntfs_ino;
1451 /* Map, pin, and lock the mft record. */
1452 m = map_mft_record(base_ni);
1453 if (IS_ERR(m)) {
1454 err = PTR_ERR(m);
1455 m = NULL;
1456 ctx = NULL;
1457 goto err_out;
1458 }
1459 /*
1460 * If a parallel write made the attribute non-resident, drop the mft
1461 * record and retry the writepage.
1462 */
1463 if (unlikely(NInoNonResident(ni))) {
1464 unmap_mft_record(base_ni);
1465 goto retry_writepage;
1466 }
1467 ctx = ntfs_attr_get_search_ctx(base_ni, m);
1468 if (unlikely(!ctx)) {
1469 err = -ENOMEM;
1470 goto err_out;
1471 }
1472 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1473 CASE_SENSITIVE, 0, NULL, 0, ctx);
1474 if (unlikely(err))
1475 goto err_out;
1476 /*
1477 * Keep the VM happy. This must be done otherwise the radix-tree tag
1478 * PAGECACHE_TAG_DIRTY remains set even though the page is clean.
1479 */
1480 BUG_ON(PageWriteback(page));
1481 set_page_writeback(page);
1482 unlock_page(page);
1483 attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
1484 i_size = i_size_read(vi);
1485 if (unlikely(attr_len > i_size)) {
1486 /* Race with shrinking truncate or a failed truncate. */
1487 attr_len = i_size;
1488 /*
1489 * If the truncate failed, fix it up now. If a concurrent
1490 * truncate, we do its job, so it does not have to do anything.
1491 */
1492 err = ntfs_resident_attr_value_resize(ctx->mrec, ctx->attr,
1493 attr_len);
1494 /* Shrinking cannot fail. */
1495 BUG_ON(err);
1496 }
1497 addr = kmap_atomic(page);
1498 /* Copy the data from the page to the mft record. */
1499 memcpy((u8*)ctx->attr +
1500 le16_to_cpu(ctx->attr->data.resident.value_offset),
1501 addr, attr_len);
1502 /* Zero out of bounds area in the page cache page. */
1503 memset(addr + attr_len, 0, PAGE_SIZE - attr_len);
1504 kunmap_atomic(addr);
1505 flush_dcache_page(page);
1506 flush_dcache_mft_record_page(ctx->ntfs_ino);
1507 /* We are done with the page. */
1508 end_page_writeback(page);
1509 /* Finally, mark the mft record dirty, so it gets written back. */
1510 mark_mft_record_dirty(ctx->ntfs_ino);
1511 ntfs_attr_put_search_ctx(ctx);
1512 unmap_mft_record(base_ni);
1513 return 0;
1514err_out:
1515 if (err == -ENOMEM) {
1516 ntfs_warning(vi->i_sb, "Error allocating memory. Redirtying "
1517 "page so we try again later.");
1518 /*
1519 * Put the page back on mapping->dirty_pages, but leave its
1520 * buffers' dirty state as-is.
1521 */
1522 redirty_page_for_writepage(wbc, page);
1523 err = 0;
1524 } else {
1525 ntfs_error(vi->i_sb, "Resident attribute write failed with "
1526 "error %i.", err);
1527 SetPageError(page);
1528 NVolSetErrors(ni->vol);
1529 }
1530 unlock_page(page);
1531 if (ctx)
1532 ntfs_attr_put_search_ctx(ctx);
1533 if (m)
1534 unmap_mft_record(base_ni);
1535 return err;
1536}
1537
1538#endif /* NTFS_RW */
1539
1540/**
1541 * ntfs_bmap - map logical file block to physical device block
1542 * @mapping: address space mapping to which the block to be mapped belongs
1543 * @block: logical block to map to its physical device block
1544 *
1545 * For regular, non-resident files (i.e. not compressed and not encrypted), map
1546 * the logical @block belonging to the file described by the address space
1547 * mapping @mapping to its physical device block.
1548 *
1549 * The size of the block is equal to the @s_blocksize field of the super block
1550 * of the mounted file system which is guaranteed to be smaller than or equal
1551 * to the cluster size thus the block is guaranteed to fit entirely inside the
1552 * cluster which means we do not need to care how many contiguous bytes are
1553 * available after the beginning of the block.
1554 *
1555 * Return the physical device block if the mapping succeeded or 0 if the block
1556 * is sparse or there was an error.
1557 *
1558 * Note: This is a problem if someone tries to run bmap() on $Boot system file
1559 * as that really is in block zero but there is nothing we can do. bmap() is
1560 * just broken in that respect (just like it cannot distinguish sparse from
1561 * not available or error).
1562 */
1563static sector_t ntfs_bmap(struct address_space *mapping, sector_t block)
1564{
1565 s64 ofs, size;
1566 loff_t i_size;
1567 LCN lcn;
1568 unsigned long blocksize, flags;
1569 ntfs_inode *ni = NTFS_I(mapping->host);
1570 ntfs_volume *vol = ni->vol;
1571 unsigned delta;
1572 unsigned char blocksize_bits, cluster_size_shift;
1573
1574 ntfs_debug("Entering for mft_no 0x%lx, logical block 0x%llx.",
1575 ni->mft_no, (unsigned long long)block);
1576 if (ni->type != AT_DATA || !NInoNonResident(ni) || NInoEncrypted(ni)) {
1577 ntfs_error(vol->sb, "BMAP does not make sense for %s "
1578 "attributes, returning 0.",
1579 (ni->type != AT_DATA) ? "non-data" :
1580 (!NInoNonResident(ni) ? "resident" :
1581 "encrypted"));
1582 return 0;
1583 }
1584 /* None of these can happen. */
1585 BUG_ON(NInoCompressed(ni));
1586 BUG_ON(NInoMstProtected(ni));
1587 blocksize = vol->sb->s_blocksize;
1588 blocksize_bits = vol->sb->s_blocksize_bits;
1589 ofs = (s64)block << blocksize_bits;
1590 read_lock_irqsave(&ni->size_lock, flags);
1591 size = ni->initialized_size;
1592 i_size = i_size_read(VFS_I(ni));
1593 read_unlock_irqrestore(&ni->size_lock, flags);
1594 /*
1595 * If the offset is outside the initialized size or the block straddles
1596 * the initialized size then pretend it is a hole unless the
1597 * initialized size equals the file size.
1598 */
1599 if (unlikely(ofs >= size || (ofs + blocksize > size && size < i_size)))
1600 goto hole;
1601 cluster_size_shift = vol->cluster_size_bits;
1602 down_read(&ni->runlist.lock);
1603 lcn = ntfs_attr_vcn_to_lcn_nolock(ni, ofs >> cluster_size_shift, false);
1604 up_read(&ni->runlist.lock);
1605 if (unlikely(lcn < LCN_HOLE)) {
1606 /*
1607 * Step down to an integer to avoid gcc doing a long long
1608 * comparision in the switch when we know @lcn is between
1609 * LCN_HOLE and LCN_EIO (i.e. -1 to -5).
1610 *
1611 * Otherwise older gcc (at least on some architectures) will
1612 * try to use __cmpdi2() which is of course not available in
1613 * the kernel.
1614 */
1615 switch ((int)lcn) {
1616 case LCN_ENOENT:
1617 /*
1618 * If the offset is out of bounds then pretend it is a
1619 * hole.
1620 */
1621 goto hole;
1622 case LCN_ENOMEM:
1623 ntfs_error(vol->sb, "Not enough memory to complete "
1624 "mapping for inode 0x%lx. "
1625 "Returning 0.", ni->mft_no);
1626 break;
1627 default:
1628 ntfs_error(vol->sb, "Failed to complete mapping for "
1629 "inode 0x%lx. Run chkdsk. "
1630 "Returning 0.", ni->mft_no);
1631 break;
1632 }
1633 return 0;
1634 }
1635 if (lcn < 0) {
1636 /* It is a hole. */
1637hole:
1638 ntfs_debug("Done (returning hole).");
1639 return 0;
1640 }
1641 /*
1642 * The block is really allocated and fullfils all our criteria.
1643 * Convert the cluster to units of block size and return the result.
1644 */
1645 delta = ofs & vol->cluster_size_mask;
1646 if (unlikely(sizeof(block) < sizeof(lcn))) {
1647 block = lcn = ((lcn << cluster_size_shift) + delta) >>
1648 blocksize_bits;
1649 /* If the block number was truncated return 0. */
1650 if (unlikely(block != lcn)) {
1651 ntfs_error(vol->sb, "Physical block 0x%llx is too "
1652 "large to be returned, returning 0.",
1653 (long long)lcn);
1654 return 0;
1655 }
1656 } else
1657 block = ((lcn << cluster_size_shift) + delta) >>
1658 blocksize_bits;
1659 ntfs_debug("Done (returning block 0x%llx).", (unsigned long long)lcn);
1660 return block;
1661}
1662
1663/**
1664 * ntfs_normal_aops - address space operations for normal inodes and attributes
1665 *
1666 * Note these are not used for compressed or mst protected inodes and
1667 * attributes.
1668 */
1669const struct address_space_operations ntfs_normal_aops = {
1670 .readpage = ntfs_readpage,
1671#ifdef NTFS_RW
1672 .writepage = ntfs_writepage,
1673 .set_page_dirty = __set_page_dirty_buffers,
1674#endif /* NTFS_RW */
1675 .bmap = ntfs_bmap,
1676 .migratepage = buffer_migrate_page,
1677 .is_partially_uptodate = block_is_partially_uptodate,
1678 .error_remove_page = generic_error_remove_page,
1679};
1680
1681/**
1682 * ntfs_compressed_aops - address space operations for compressed inodes
1683 */
1684const struct address_space_operations ntfs_compressed_aops = {
1685 .readpage = ntfs_readpage,
1686#ifdef NTFS_RW
1687 .writepage = ntfs_writepage,
1688 .set_page_dirty = __set_page_dirty_buffers,
1689#endif /* NTFS_RW */
1690 .migratepage = buffer_migrate_page,
1691 .is_partially_uptodate = block_is_partially_uptodate,
1692 .error_remove_page = generic_error_remove_page,
1693};
1694
1695/**
1696 * ntfs_mst_aops - general address space operations for mst protecteed inodes
1697 * and attributes
1698 */
1699const struct address_space_operations ntfs_mst_aops = {
1700 .readpage = ntfs_readpage, /* Fill page with data. */
1701#ifdef NTFS_RW
1702 .writepage = ntfs_writepage, /* Write dirty page to disk. */
1703 .set_page_dirty = __set_page_dirty_nobuffers, /* Set the page dirty
1704 without touching the buffers
1705 belonging to the page. */
1706#endif /* NTFS_RW */
1707 .migratepage = buffer_migrate_page,
1708 .is_partially_uptodate = block_is_partially_uptodate,
1709 .error_remove_page = generic_error_remove_page,
1710};
1711
1712#ifdef NTFS_RW
1713
1714/**
1715 * mark_ntfs_record_dirty - mark an ntfs record dirty
1716 * @page: page containing the ntfs record to mark dirty
1717 * @ofs: byte offset within @page at which the ntfs record begins
1718 *
1719 * Set the buffers and the page in which the ntfs record is located dirty.
1720 *
1721 * The latter also marks the vfs inode the ntfs record belongs to dirty
1722 * (I_DIRTY_PAGES only).
1723 *
1724 * If the page does not have buffers, we create them and set them uptodate.
1725 * The page may not be locked which is why we need to handle the buffers under
1726 * the mapping->private_lock. Once the buffers are marked dirty we no longer
1727 * need the lock since try_to_free_buffers() does not free dirty buffers.
1728 */
1729void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
1730 struct address_space *mapping = page->mapping;
1731 ntfs_inode *ni = NTFS_I(mapping->host);
1732 struct buffer_head *bh, *head, *buffers_to_free = NULL;
1733 unsigned int end, bh_size, bh_ofs;
1734
1735 BUG_ON(!PageUptodate(page));
1736 end = ofs + ni->itype.index.block_size;
1737 bh_size = VFS_I(ni)->i_sb->s_blocksize;
1738 spin_lock(&mapping->private_lock);
1739 if (unlikely(!page_has_buffers(page))) {
1740 spin_unlock(&mapping->private_lock);
1741 bh = head = alloc_page_buffers(page, bh_size, 1);
1742 spin_lock(&mapping->private_lock);
1743 if (likely(!page_has_buffers(page))) {
1744 struct buffer_head *tail;
1745
1746 do {
1747 set_buffer_uptodate(bh);
1748 tail = bh;
1749 bh = bh->b_this_page;
1750 } while (bh);
1751 tail->b_this_page = head;
1752 attach_page_buffers(page, head);
1753 } else
1754 buffers_to_free = bh;
1755 }
1756 bh = head = page_buffers(page);
1757 BUG_ON(!bh);
1758 do {
1759 bh_ofs = bh_offset(bh);
1760 if (bh_ofs + bh_size <= ofs)
1761 continue;
1762 if (unlikely(bh_ofs >= end))
1763 break;
1764 set_buffer_dirty(bh);
1765 } while ((bh = bh->b_this_page) != head);
1766 spin_unlock(&mapping->private_lock);
1767 __set_page_dirty_nobuffers(page);
1768 if (unlikely(buffers_to_free)) {
1769 do {
1770 bh = buffers_to_free->b_this_page;
1771 free_buffer_head(buffers_to_free);
1772 buffers_to_free = bh;
1773 } while (buffers_to_free);
1774 }
1775}
1776
1777#endif /* NTFS_RW */